get list of subdirectories in msbuild

Question

Given a list of directories:

<ItemGroup>
  <Dirs Include="Foo\Dir1" />
  <Dirs Include="Foo\Dir2" />
</ItemGroup>

How can I get a list of all subdirectories.

Transforming this list with "$(Identity)\**" does not match anything and transforming with "$(Identity)\**\*" and then with RelativeDir yields only directories that contain files.

Currently I have to resort to C#:

<UsingTask TaskName="GetSubdirectories" TaskFactory="CodeTaskFactory"
    AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll">
    <ParameterGroup>
        <Directories ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="true" />
        <SubDirectories ParameterType="Microsoft.Build.Framework.ITaskItem[]" Output="true" />
    </ParameterGroup>
    <Task>
        <Code Type="Fragment" Language="cs"><![CDATA[
            var result = new List<ITaskItem>();
            foreach (var dirItem in Directories) {
                foreach (var dir in Directory.GetDirectories(dirItem.ItemSpec, "*", SearchOption.AllDirectories)) {
                    if (dir.Contains(@"\.svn\") || dir.EndsWith(@"\.svn")) continue;
                    result.Add(new TaskItem(dir));
                }
            }
            SubDirectories = result.ToArray();
        ]]></Code>
    </Task>
</UsingTask>

<GetSubdirectories Directories="@(Dirs)">
    <Output TaskParameter="SubDirectories" ItemName="SubDirs" />
</GetSubdirectories>

But I would like to know if there is an easier way.

Answer 1

Excerpted from the book "MSBuild Trickery":

<Import Project="EnableAllPropertyFunctions.tasks" />

<Target Name="GetSubdirectories">
   <ItemGroup>
      <Dirs Include="$([System.IO.Directory]::
         EnumerateDirectories(
            `.\Foo`,
            `*`,
            System.IO.SearchOption.AllDirectories))"
            />
   </ItemGroup>

   <Message Text="%(Dirs.Identity)" />
</Target>

You'll need to first enable the extended property function set by ensuring that the environment variable MSBuildEnableAllPropertyFunctions is set to the value 1 (that is what the imported .tasks file accomplishes, with an inline task).

Once @(Dirs) is set up, you can filter it with the Remove attribute to get rid of the Subversion folders.

Answer 2

<CreateItem Include="$(OutputFolder)\*\*.*">
  <Output TaskParameter="Include" ItemName="FilesInSubFolders" />
</CreateItem>

<RemoveDuplicates Inputs="@(FilesInSubFolders->'%(RelativeDir)')">
  <Output TaskParameter="Filtered" ItemName="SubDirs"/>
</RemoveDuplicates>

<Message Text="@(SubDirs)"/>

This will put all the immediate subfolder paths into @(SubDirs). If you change Include="$(OutputFolder)\*\*.*" to Include="$(OutputFolder)\**\*.*", it'll include all subfolders recursively.